Area of the red square can be computed as follows:
area of a square = L²
Since one side of each triangle forms a part of the triangle knowing the length of sides of the green and yellow triangle can be use to get the sides of the red square and invariably the area.
Green square
L² = 9
square both sides
√L² = √9
L = 3 ft
Yellow square
L² = 25
square both sides
√L² = √25
L = 5 ft
use Pythagoras theorem to get the third side of the triangle which is the b
